Destination tag
A number some coins like XRP need on top of the address, so a pooled wallet knows the money is yours.
On some chains, like the XRP Ledger, you can attach a destination tag (or memo) to a payment. Casinos and exchanges often run everybody's deposits through a single address, and that number is how they figure out who sent what. Other chains have their own memo field.
Forget it and your money's stuck
No tag? The coins land in the casino's wallet, but your balance stays at zero. Now support has to fix it manually, and some sites charge you for that or won't do it at all. Interac has nothing like this. It's a crypto-only trap.
Here's how it happens
The cashier gives you an XRP address and tag 4815162. You paste the address, hit send, and skip the tag. The ledger says done. Your casino account says nothing. You write to support with the transaction hash, and someone has to dig up your coins and add them manually.
Don't get caught
- Copy the address first, then the tag, and double-check each one.
- Going to an exchange? Enter the tag that exchange shows you on its deposit page.
- Going to your own wallet? Most of the time no tag is needed.